Electromagnetic device



June 14, 1938.v B, WSHELEWCH 2,120,339

ELECTROMAGNETIC DEVICE Filed NOV. 30, 1935 INVENTOR mmm/ELM IS ATTO R N EY enjalrzin M'shelich Patented June 14, 1938 UNITED STATES PATENT OFFICE to The Union Switch & Signal Company,

Swissvale, Pa., a corporation of Pennsylvania Application November 30, 1935, Serial No. 52.385

7 Claims.

5- magnetic ux path by a back strap.

An object of my invention is to provide new and novel means for connecting the back strap to the permanent magnet and to the cores of the electromagnet in such a manner as to provide highly eiiicient magnetic paths between the cores.

I will describe one form of electromagnetic device embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. l. is an isometric view, partly in section, illustrating one form of apparatus embodying my invention; while Fig. 1a is a detailed view, partly in section,

fof a portion of the apparatus embodying my invention not visible in Fig. l.

Similar reference characters refer to similar parts in each of the views.

Referring to the drawing, the reference character A designates a polarized relay having the usual enclosing frame of which the top plate S is the only part shown in the drawing. The relay comprises an electromagnet having cores Ia and Ib, which pass through suitable holes in the top plate S and terminate in pole pieces 2a and 2b on the underside of the top plate. The cores Ia and Ib are provided with the usual windings 4a, and 4b, respectively. The relay also comprises a permanent magnet II which passes through a hole in the top plate S and terminates in a pole piece I2 on the underside of this top plate. The permanent magnet II and the cores Ia and Ib are rigidly attached to the top plate S by the usual threaded rings R, the ring on the permanent magnet being the only one which is illustrated in the drawing. The upper ends of the cores Ia and Ib and the upper end of the permanent magnet II are connected by a triangular back strap 3. The upper ends of the cores and the permanent magnet, as well as the under surface of the back strap 3, are ground to insure good mechanical and magnetic contact. For the purpose of high electromagnetic efficiency of the relay as a whole, the operating coils la and 4b preferably occupy the entire space between the top plate S and the back strap 3. The permanent magnet I I is, however, not provided with an operating coil, and in accordance with my invention this magnet is used to hold. the back strap firmly in engagement with the upper ends of the cores Ia and Ib and the magnet II. For this purpose I provide a mechanical link extending between the magnet II and the back strap 3. The main portion of this link consists of a clamp ing member I8 surrounding the permanent magnet II at a point slightly below the top thereof.

As clearly illustrated in Fig. la, the member I8 is held in xed relation to permanent magnet II by a cap screw I9 threaded through the member I3 and engaging a shallow indentation 20 in the side of the permanent magnet Il. A second cap screw 2I passes through a hole 23 in the back strap 3 and is threaded into a tapped hole in the member I8. When the cap screw 2| is tightly drawn down it holds the back strap 3 in rm contact with permanent magnet I! and cores Ia and Ib, respectively.

Other structural details of the relay may take any one of several forms. In the present disclosure, attached to the one side of the pole pieces 2a and 2b, respectively, there is a non-magnetizable bracket 'I which carries two pivot screws 8, only one of which is visible in the drawing. Pivotally mounted on the screws B for swinging movement toward or away from the pole pieces 2a and 2b is a neutral armature 9 which may be used to actuate circuit switching contacts, and which is picked up whenever coils llc` and 4b are energized.

The permanent magnet II at its lower end is provided with a bifurcated pole piece I2. Plvotally supported between the bifurcations of the pole piece I2 on the ends of two pivot screws I3, only one of which is visible in the drawing, is a polarized armature I4, which may be used to actuate circuit switching contacts. 'Ihe pole pieces 2a and 2b of cores Ia and Ib, respectively, are provided with integral extensions I5a` and I5b, respectively, the pole faces of which overlie the opposite ends of the armature I4. When the coils 4a and 4b are energized, the polarized armature I4 will swing toward one or the other of these extensions, depending upon the polarity of the current which is supplied to coils 4a and Ib, respectively.

The magnetic flux path for eiiecting the operation of armature 9 includes pole piece 2a., the core Ia, a portion of back strap 3, core Ib, and pole piece 2b, respectively. By use of the hereinbefore described novel means of holding the back strap 3 in firm engagement with the top ends of the cores Ia and Ibi, it is unnecessary to drill and tap these cores or to perforate the backstrap at these points in order to hold the back strap 3 to the cores Ia and Ib. and therefore, I have provided a highly efcient magnetic path between cores I a and Ib.

There are two magnetic ux paths for effecting the operation of armature I4. The one path includes the pole piece extension I5a, pole piece 2a, core Ia, a portion of the back strap 3, permanent magnet II, and the pole piece I2; while the other path includes pole piece extension |51), pole piece 2b, core Ib, a portion of the back strap 3, permanent magnet II, and pole piece I2. It will be seen that, since each of the traced magnetic flux paths over which the armature id may be operated includes the hack strap il and one of the electromagnet cores, the operating efficiency of the device as regards armature lli is also improved as a result of the improved man ner in which the back strap 3 is held ilrinly against permanent magnet il and the eiectromagnet cores la and ib, respectively.

Although i have herein shown and described only one form of electromagnetic device embodying my invention, it is understood that various changes and modications may made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described. my invention, what 'L claim is:

l. In an electromagnetic device, a permanent magnet and two electromagnet cores, means for rigidly securing said permanent magnet and said electremagnet cores together in parallel relation, a back strap spaced from said securing means for magnetically coupling the ends oi said permanent magnet and cores together, a back strap clamping member having a hole through which said permanent magnet passes, a nrst screw threaded through said clamping member and engaging said permanent magnet for holding said clamping member in fixed relation with respect to said permanent magnet; and a second screw passing through a hole in said hack strap and threaded into said clamping memser for holding said back strap against said permanent magnet and electromagnet cores respectively.

2. In an electromagnetic device, two magnetic flux carrying elements, means for rigidly7 securing said elements together in parallel relation, a backv strap spaced from said securing means for connecting the ends of said elements together, an armature associated with hoth or" said elements, a coil on one of said elements for operating said armature; and means including a clamping member surrounding the other of said elements, a rst screw threaded through said clamping member into engagement with said other of said elements, and a second screw passing through said back strap and threaded into said clamping member, for holding back strap in rm contact with said elements to for n. an eiiicient magnetic path between said eiements.

3, An electromagnetic device comprising two parallel magnetizable cores and a permanent magnet secured adjacent one end to an insulating top plate and provided at their opposite ends with ground surfaces all lying in the same plane, a hack strap of magnetizable material having a ground surface which engages said. cores at their ground surfaces to provide a good magnetic contact between said cores and said magnet, and a clamping member secured to said back strap at a point spaced from said cores and said magnet and to said permanent magnet intermediate its ends for irmly holding said. back strap in engagement with said cores and said magnet.

1i. An electromagnetic device comprising plurality of iiux carrying elements rigidly secured to a supporting member in parallel relation and provided at one end with ground surfaces all lying in the same plane, a back strap of magneticM able material provided with a ground surface which engages the ground surfaces of said elements to magnetically connect the elements to gether, and a clamping member secured to one or said elements intermediate its ends and to said back strap at a point spaced from all oi said elements for holding said back. strap in engagement with said elements.

5. An electromagnetic device comprising two parallel electromagnet cores and a permanent magnet secured adjacent one end to an insulating top plate and provided at their opposite ends with ground surfaces, a back strap of magnetizable material having group surface which enn gages said cores and said permanent magnet at their ground surfaces to provide a good magnetic coupling between said cores and said magnet, energizing coils disposed on said electromagnet cores for energizing said cores and extending into close proximity to said haci: strap, a hack strap clamping member having an opening through which said permanent magnet passes, means i'or securing said clamping memher to said permanent magnet, a screw passing through a hole in said bach strap and threaded into said clamping member for irmly holding said hack strap in engagement with said electromagnet cores and said permanent magnet, armatures associated with said permanent magnet and said electromagnet cores and controlled by the uxes traversing these elements.

G. An electromagnetic device comprising two parallel eieetrolnagnet cores and a permanent magnet secured adjacent one end to an insulating top plate in triangular spaced relation and provided at their opposite ends with ground surfaces, a hack strap of magnetizahle material havl ing a ground surface which engages said cores and said permanent magnet at their ground surfaces to provide a good magnetic coupling be tween said cores and said magnet, energizing coils disposed on said electromagnet co for energiaing said cores and extending into close proximity to said baci; strap, a back strap clamping member having a hole through which said permanent magnet passes, a first screw threaded through said clamping member and engaging said permanent magnet for securing said clamping membei' to said permanent magnet, a second screw passing through a hole in said back strap substantially equally spaced from said two Cores and said permanent magnet and threaded into said clamping member ior holding said hack strap in engagement with said cores and said permanent magnet, and armatures associated with said electromagnet cores and said permanent magnet and controlled by the fluxes traversing these elements.

'7. An electromagnetic device comprising a plu rality of flux carrying elements rigidly secured to a supporting member in parallel relation, a hack strap of magnetiaahle material engaging the ends oi said elements to magnetically couple said elements together, and a clamping member cured to one of said elements intermediate its ends and to said back: strap at a point spaced lrom all of said elements for holding said hack strap in engagement with said elements.

BEN J AMIN 'i3/IIS-IELEVCH4 

